Articulating surgical stapling instrument incorporating a two-piece e-beam firing mechanism

ABSTRACT

A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. An E-beam firing bar moves distally through the clamped end effector to sever tissue and to drive staples on each side of the cut. The E-beam firing bar affirmatively spaces the anvil from the elongate channel to assure properly formed closed staples, especially when an amount of tissue is clamped that is inadequate to space the end effector. In particular, an upper pin of the firing bar longitudinally moves through an anvil slot and a channel slot is captured between a lower cap and a middle pin of the firing bar to assure a minimum spacing. Forming the E-beam from a thickened distal portion and a thinned proximal strip enhances manufacturability and facilitates use in such articulating surgical instruments.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application under 35 U.S.C.§120 of U.S. patent application Ser. No. 14/175,148, entitled SURGICALSTAPLING INSTRUMENT, filed Feb. 7, 2014, now U.S. Patent ApplicationPublication No. 2014/0151434, which is a continuation application under35 U.S.C. §120 of U.S. patent application Ser. No. 13/369,601, entitledROBOTICALLY-CONTROLLED SURGICAL END EFFECTOR SYSTEM, filed on Feb. 9,2012, which issued on Jul. 22, 2014 as U.S. Pat. No. 8,783,541, which isa continuation application under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 13/118,246, entitled ROBOTICALLY-DRIVEN SURGICALINSTRUMENT WITH E-BEAM DRIVER, filed on May 27, 2011, now U.S. PatentApplication Publication No. 2011/0290853, which is acontinuation-in-part application under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 11/538,154, entitled ARTICULATING SURGICAL STAPLINGINSTRUMENT INCORPORATING A TWO-PIECE E-BEAM FIRING MECHANISM, filed onOct. 3, 2006, the entire disclosures of which are incorporated byreference herein. The present application is a continuation applicationunder 35 U.S.C. §120 of U.S. patent application Ser. No. 14/175,148,entitled SURGICAL STAPLING INSTRUMENT, filed Feb. 7, 2014, now U.S.Patent Application Publication No. 2014/0151434, which is a continuationapplication under 35 U.S.C. §120 of U.S. patent application Ser. No.11/141,753, entitled SURGICAL STAPLING INSTRUMENT HAVING ANELECTROACTIVE POLYMER ACTUATED MEDICAL SUBSTANCE DISPENSER, filed onJun. 1, 2005, now U.S. Patent Application Publication No. 2006/0025813,which claims the benefit under 35 U.S.C. §119(e) of U.S. ProvisionalPatent Application Ser. No. 60/591,694, entitled SURGICAL INSTRUMENTINCORPORATING AN ELECTRICALLY ACTUATED ARTICULATION MECHANISM, filed onJul. 28, 2004, the entire disclosures of which are incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates in general to surgical instruments thatare suitable for endoscopically inserting an end effector that isactuated by a longitudinally driven firing member, and more particularlya surgical stapling and severing instrument that has an articulatingshaft.

BACKGROUND OF THE INVENTION

Endoscopic surgical instruments are often preferred over traditionalopen surgical devices since a smaller incision tends to reduce thepost-operative recovery time and complications. Consequently,significant development has gone into a range of endoscopic surgicalinstruments that are suitable for precise placement of a distal endeffector at a desired surgical site through a cannula of a trocar. Thesedistal end effectors engage the tissue in a number of ways to achieve adiagnostic or therapeutic effect (e.g., endocutter, grasper, cutter,staplers, clip applier, access device, drug/gene therapy deliverydevice, and energy device using ultrasound, RF, laser, etc.).

Positioning the end effector is constrained by the trocar. Generallythese endoscopic surgical instruments include a long shaft between theend effector and a handle portion manipulated by the clinician. Thislong shaft enables insertion to a desired depth and rotation about thelongitudinal axis of the shaft, thereby positioning the end effector toa degree. With judicious placement of the trocar and use of graspers,for instance, through another trocar, often this amount of positioningis sufficient. Surgical stapling and severing instruments, such asdescribed in U.S. Pat. No. 5,465,895, are an example of an endoscopicsurgical instrument that successfully positions an end effector byinsertion and rotation.

More recently, U.S. patent application Ser. No. 10/443,617, entitledSURGICAL STAPLING INSTRUMENT INCORPORATING AN E-BEAM FIRING MECHANISM,filed on May 20, 2003, now U.S. Pat. No. 6,978,921, which isincorporated by reference in its entirety, describes an improved“E-beam” firing bar for severing tissue and actuating staples. Some ofthe additional advantages include affirmatively spacing the jaws of theend effector, or more specifically a staple applying assembly, even ifslightly too much or too little tissue is clamped for optimal stapleformation. Moreover, the E-beam firing bar engages the end effector andstaple cartridge in a way that enables several beneficial lockouts to beincorporated.

Depending upon the nature of the operation, it may be desirable tofurther adjust the positioning of the end effector of an endoscopicsurgical instrument. In particular, it is often desirable to orient theend effector at an axis transverse to the longitudinal axis of the shaftof the instrument. The transverse movement of the end effector relativeto the instrument shaft is conventionally referred to as “articulation”.This is typically accomplished by a pivot (or articulation) joint beingplaced in the extended shaft just proximal to the staple applyingassembly. This allows the surgeon to articulate the staple applyingassembly remotely to either side for better surgical placement of thestaple lines and easier tissue manipulation and orientation. Thisarticulated positioning permits the clinician to more easily engagetissue in some instances, such as behind an organ. In addition,articulated positioning advantageously allows an endoscope to bepositioned behind the end effector without being blocked by theinstrument shaft.

Approaches to articulating a surgical stapling and severing instrumenttend to be complicated by integrating control of the articulation alongwith the control of closing the end effector to clamp tissue and firethe end effector (i.e., stapling and severing) within the small diameterconstraints of an endoscopic instrument. Generally, the three controlmotions are all transferred through the shaft as longitudinaltranslations. For instance, U.S. Pat. No. 5,673,840 discloses anaccordion-like articulation mechanism (“flex-neck”) that is articulatedby selectively drawing back one of two connecting rods through theimplement shaft, each rod offset respectively on opposite sides of theshaft centerline. The connecting rods ratchet through a series ofdiscrete positions.

Another example of longitudinal control of an articulation mechanism isU.S. Pat. No. 5,865,361 that includes an articulation link offset from acamming pivot such that pushing or pulling longitudinal translation ofthe articulation link effects articulation to a respective side.Similarly, U.S. Pat. No. 5,797,537 discloses a similar rod passingthrough the shaft to effect articulation.

In commonly owned U.S. patent application Ser. No. 10/615,973, entitledSURGICAL INSTRUMENT INCORPORATING AN ARTICULATION MECHANISM HAVINGROTATION ABOUT THE LONGITUDINAL AXIS, now U.S. Pat. No. 7,111,769, thedisclosure of which is hereby incorporated by reference in its entirety,a rotational motion is used to transfer articulation motion as analternative to a longitudinal motion.

In the application entitled SURGICAL STAPLING INSTRUMENT INCORPORATINGAN E-BEAM FIRING MECHANISM, U.S. patent application Ser. No. 10/443,617,filed on May 20, 2003, now U.S. Pat. No. 6,978,921, the disclosure ofwhich was previously incorporated by reference in its entirety, asurgical severing and stapling instrument, suitable for laparoscopic andendoscopic clinical procedures, clamps tissue within an end effector ofan elongate channel pivotally opposed by an anvil. An E-beam firing barmoves distally through the clamped end effector to sever tissue and todrive staples on each side of the cut. The E-beam firing baraffirmatively spaces the anvil from the elongate channel to assureproperly formed closed staples, especially when an amount of tissue isclamped that is inadequate to space the end effector. In particular, anupper pin of the firing bar longitudinally moves through an anvil slotand a channel slot is captured between a lower cap and a middle pin ofthe firing bar to assure a minimum spacing. While this E-beam firing barhas a number of advantages, additional features are desirable to enhancemanufacturability and to minimize dimensional variations.

Consequently, a significant need exists for a surgical instrument with afiring bar that advantageously assures proper spacing between clampedjaws of an end effector and which facilitates articulation of its shaft.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective view of an endoscopic surgical staplinginstrument for surgical stapling and severing in an open, unarticulatedstate.

FIG. 2 is a left, front perspective view of an open staple applyingassembly of the surgical stapling instrument of FIG. 1 with a right halfportion of a replaceable staple cartridge included in a staple channel.

FIG. 3 is an exploded perspective view of the staple applying assemblyof FIG. 2 with a complete replaceable staple cartridge and analternative nonarticulating shaft configuration.

FIG. 4 is a perspective view of a two-piece knife and firing bar(“E-beam”) of the staple applying assembly of FIG. 2.

FIG. 5 is a perspective view of a wedge sled of a staple cartridge ofthe staple applying assembly of FIG. 1.

FIG. 6 is a left side view in elevation taken in longitudinal crosssection along a centerline line 6-6 of the staple applying assembly ofFIG. 2.

FIG. 7 is a perspective view of the open staple applying assembly ofFIG. 2 without the replaceable staple cartridge, a portion of the staplechannel proximate to a middle pin of two-piece knife and firing bar, andwithout a distal portion of a staple channel.

FIG. 8 is a front view in elevation taken in cross section along line8-8 of the staple applying assembly of FIG. 2 depicting internal stapledrivers of the staple cartridge and portions of the two-piece knife andfiring bar.

FIG. 9 is a left side view in elevation taken generally along thelongitudinal axis of line 6-6 of a closed staple applying assembly ofFIG. 2 to include center contact points between the two-piece knife andwedge sled but also laterally offset to show staples and staple driverswithin the staple cartridge.

FIG. 10 is a left side detail view in elevation of the staple applyingassembly of FIG. 9 with the two-piece knife retracted slightly more astypical for staple cartridge replacement.

FIG. 11 is a left side detail view in elevation of the staple applyingassembly of FIG. 10 with the two-piece knife beginning to fire,corresponding to the configuration depicted in FIG. 9.

FIG. 12 is a left side cross-sectional view in elevation of the closedstaple applying assembly of FIG. 9 after the two-piece knife and firingbar has distally fired.

FIG. 13 is a left side cross-sectional view in elevation of the closedstaple applying assembly of FIG. 12 after firing of the staple cartridgeand retraction of the two-piece knife.

FIG. 14 is a left side cross-sectional detail view in elevation of thestaple applying assembly of FIG. 13 with the two-piece knife allowed todrop into a lockout position.

FIG. 15 is a top view in section taken along lines 15-15 of anarticulation joint (flex neck) of the surgical stapling instrument ofFIG. 1.

FIG. 16 is a front view in elevation taken in vertical cross sectionalong lines 16-16 of the articulation joint of FIG. 15, showingelectroactive polymer (EAP) plate articulation actuators and EAP supportplates for a firing bar.

FIG. 17 is a top view in section along lines 15-15 of the articulationjoint of FIG. 16 after articulation.

FIG. 18 is a perspective view of the articulation joint of FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

The entire disclosure of U.S. patent application Ser. No. 11/082,495,entitled SURGICAL INSTRUMENT INCORPORATING AN ELECTRICALLY ACTUATEDARTICULATION MECHANISM, filed on Mar. 17, 2005, now U.S. Pat. No.7,506,790, is incorporated herein by reference. The entire disclosure ofU.S. Pat. No. 6,667,825, entitled STABLE CONJUGATED POLYMERELECTROCHROMIC DEVICES INCORPORATING IONIC LIQUIDS, issued on Jan. 3,2002, is incorporated herein by reference. The entire disclosure of U.S.patent application Ser. No. 11/061,908, entitled SURGICAL INSTRUMENTINCORPORATING A FLUID TRANSFER CONTROLLED ARTICULATION MECHANISM, filedon Feb. 18, 2005, now U.S. Pat. No. 7,559,450, is incorporated herein byreference.

In FIGS. 1-3, a surgical stapling instrument 10 has at its distal end anend effector, depicted as a staple applying assembly 12, spaced apartfrom a handle 14 (FIG. 2) by an elongate shaft 16. The staple applyingassembly 12 includes a staple channel 18 for receiving a replaceablestaple cartridge 20. Pivotally attached to the staple channel 18 is ananvil 22 that clamps tissue to the staple cartridge 20 and serves todeform staples 23 (FIG. 3) driven up from staple holes 24 in the staplecartridge 20 against staple forming recesses 26 (FIG. 6) in an anvilundersurface 28 into a closed shape. When the staple applying assembly12 is closed, its cross sectional area, as well as the elongate shaft 16are suitable for insertion through a small surgical opening, such asthrough a cannula of a trocar (not shown).

With particular reference to FIG. 1, correct placement and orientationof the staple applying assembly 12 is facilitated by controls on thehandle 14. In particular, a rotation knob 30 causes rotation of theshaft 16 about its longitudinal axis, and hence rotation of the stapleapplying assembly 12. Additional positioning is enabled at anarticulation joint 32 in the shaft 16 that pivots the staple applyingassembly 12 in an arc from the longitudinal axis of the shaft 16,thereby allowing placement behind an organ or allowing other instrumentssuch as an endoscope (not shown) to be oriented behind the stapleapplying assembly 12. This articulation is advantageously effected by anarticulation control switch 34 on the handle 14 that transmits anelectrical signal to the articulation joint 32 to an ElectroactivePolymer (EAP) actuator 36, powered by an EAP controller and power supply38 contained within the handle 14.

Once positioned with tissue in the staple applying assembly 12, asurgeon closes the anvil 22 by drawing a closure trigger 40 proximallytoward a pistol grip 42. Once clamped thus, the surgeon may grasp a moredistally presented firing trigger 44, drawing it back to effect firingof the staple applying assembly 12, which in some applications isachieved in one single firing stroke and in other applications bymultiple firing strokes. Firing accomplishes simultaneously stapling ofat least two rows of staples while severing the tissue therebetween.

Retraction of the firing components may be automatically initiated uponfull travel. Alternatively, a retraction lever 46 may be drawn aft toeffect retraction. With the firing components retracted, the stapleapplying assembly 12 may be unclamped and opened by the surgeon slightlydrawing the closure trigger 40 aft toward the pistol grip 42 anddepressing a closure release button 48 and then releasing the closuretrigger 40, thereby releasing the two stapled ends of severed tissuefrom the staple applying assembly 12.

Staple Applying Assembly

While an articulation joint 32 is depicted in FIG. 1, for clarity and asan alternative application, the surgical stapling instrument 10 of FIGS.2-14 omit an articulation joint 32. It should be appreciated, however,that aspects of the present invention have particular advantages forarticulation as described below with regard to FIGS. 15-18.

In FIGS. 1-3, the staple applying assembly 12 accomplishes the functionsof clamping onto tissue, driving staples and severing tissue by twodistinct motions transferred longitudinally down the shaft 16 over ashaft frame 70. This shaft frame 70 is proximally attached to the handle14 and coupled for rotation with the rotation knob 30. An illustrativemulti-stroke handle 14 for the surgical stapling and severing instrument10 of FIG. 1 is described in greater detail in the co-owned U.S. patentapplication Ser. No. 10/674,026, entitled SURGICAL STAPLING INSTRUMENTINCORPORATING A MULTISTROKE FIRING POSITION INDICATOR AND RETRACTIONMECHANISM, now U.S. Pat. No. 7,364,061, the disclosure of which ishereby incorporated by reference in its entirety, with additionalfeatures and variation as described herein. While a multi-stroke handle14 advantageously supports applications with high firing forces over along distance, applications consistent with the present invention mayincorporate a single firing stroke, such as described in commonly ownedU.S. patent application Ser. No. 10/441,632, entitled SURGICAL STAPLINGINSTRUMENT HAVING SEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, now U.S.Pat. No. 7,000,818, the disclosure of which is hereby incorporated byreference in its entirety.

With particular reference to FIG. 3, the distal end of the shaft frame70 is attached to the staple channel 18. The anvil 22 has a proximalpivoting end 72 that is pivotally received within a proximal end 74 ofthe staple channel 18, just distal to its engagement to the shaft frame70. The pivoting end 72 of the anvil 22 includes a closure feature 76proximate but distal to its pivotal attachment with the staple channel18. Thus, a closure tube 78, whose distal end includes a horseshoeaperture 80 that engages this closure feature 76, selectively imparts anopening motion to the anvil 22 during proximal longitudinal motion and aclosing motion to the anvil 22 during distal longitudinal motion of theclosure tube 78 sliding over the shaft frame 70 in response to theclosure trigger 40.

The shaft frame 70 encompasses and guides a firing motion from thehandle 14 through a longitudinally reciprocating, two-piece knife andfiring bar 90. In particular, the shaft frame 70 includes a longitudinalfiring bar slot 92 that receives a proximal portion of the two-pieceknife and firing bar 90, specifically a laminate tapered firing bar 94.It should be appreciated that the laminated tapered firing bar 94 may besubstituted with a solid firing bar or of other materials inapplications not intended to pass through an articulation joint, such asdepicted in FIGS. 2-14.

An E-beam 102 is the distal portion of the two-piece knife and firingbar 90, which facilitates separate closure and firing as well as spacingof the anvil 22 from the elongate staple channel 18 during firing. Withparticular reference to FIGS. 3-4, in addition to any attachmenttreatment such as brazing or an adhesive, the knife and firing bar 90are formed of a female vertical attachment aperture 104 proximallyformed in the E-beam 102 that receives a corresponding male attachmentmember 106 distally presented by the laminated tapered firing bar 94,allowing each portion to be formed of a selected material and processsuitable for their disparate functions (e.g., strength, flexibility,friction). The E-beam 102 may be advantageously formed of a materialhaving suitable material properties for forming a pair of top pins 110,a pair of middle pins 112 and a bottom pin or foot 114, as well as beingable to acquire a sharp cutting edge 116. In addition, integrally formedand proximally projecting top guide 118 and middle guide 120 bracketingeach vertical end of the cutting edge 116 further define a tissuestaging area 122 assisting in guiding tissue to the sharp cutting edge116 prior to being severed. The middle guide 120 also serves to engageand fire the staple applying apparatus 12 by abutting a stepped centralmember 124 of a wedge sled 126 (FIG. 5) that effects staple formation bythe staple applying assembly 12, as described in greater detail below.

Forming these features (e.g., top pins 110, middle pins 112, and bottomfoot 114) integrally with the E-beam 102 facilitates manufacturing attighter tolerances relative to one another as compared to beingassembled from a plurality of parts, ensuring desired operation duringfiring and/or effective interaction with various lockout features of thestaple applying assembly 12.

In FIGS. 6-7, the surgical stapling instrument 10 is shown open, withthe E-beam 102 fully retracted. During assembly, the lower foot 114 ofthe E-beam 102 is dropped through a widened hole 130 in the staplechannel 18 and the E-beam 102 is then advanced such that the E-beam 102slides distally along a lower track 132 formed in the staple channel 18.In particular, the lower track 132 includes a narrow slot 133 that opensup as a widened slot 134 on an undersurface of the staple channel 18 toform an inverted T-shape in lateral cross section, as depictedparticularly in FIGS. 7 and 8, which communicates with the widened hole130. Once assembled, the components proximally coupled to the laminatetapered firing bar 94 do not allow the lower foot 114 to proximallytravel again to the widened hole 130 to permit disengagement.

In FIG. 9, the laminate tapered firing bar 94 facilitates insertion ofthe staple applying assembly 12 through a trocar. In particular, a moredistal, downward projection 136 raises the E-beam 102 when fullyretracted. This is accomplished by placement of the downward projection136 at a point where it cams upwardly on a proximal edge of the widenedhole 130 in the staple channel 18.

In FIG. 10, the laminate tapered firing bar 94 also enhances operationof certain lockout features that may be incorporated into the staplechannel 18 by including a more proximal upward projection 138 that isurged downwardly by the shaft frame 70 during an initial portion of thefiring travel. In particular, a lateral bar 140 is defined between apair of square apertures 142 in the shaft frame 70 (FIG. 3). A clipspring 144 that encompasses the lateral bar 140 downwardly urges aportion of the laminate tapered firing bar 94 projecting distally out ofthe longitudinal firing bar slot 92, which ensures certain advantageouslockout features are engaged when appropriate. This urging is morepronounced or confined solely to that portion of the firing travel whenthe upward projection 138 contacts the clip spring 144.

In FIGS. 6-7, the E-beam 102 is retracted with the top pins 110 thereofresiding within an anvil pocket 150 near the pivoting proximal end ofthe anvil 22. A downwardly open vertical anvil slot 152 (FIG. 2)laterally widens in the anvil 22 into an anvil internal track 154 thatcaptures the top pins 110 of the E-beam 102 as they distally advanceduring firing, as depicted in FIGS. 9-10, affirmatively spacing theanvil 22 from the staple channel 18. Thus, with the E-beam 102retracted, the surgeon is able to repeatably open and close the stapleapplying assembly 12 until satisfied with the placement and orientationof tissue captured therein for stapling and severing, yet the E-beam 102assists in proper positioning of tissue even for a staple applyingassembly 12 of reduced diameter and correspondingly reduced rigidity.

In FIGS. 2-3, 5-6, 8-14, the staple applying assembly 12 is shown withthe replaceable staple cartridge 20 that includes the wedge sled 126.Longitudinally aligned and parallel plurality of downwardly open wedgeslots 202 (FIG. 8) receive respective wedges 204 integral to the wedgesled 126. In FIGS. 8-10, the wedge sled 126 thus cams upwardly aplurality of staple drivers 206 that are vertically slidable withinstaple driver recesses 208. In this illustrative version, each stapledriver 206 includes two vertical prongs, each translating upwardly intoa respective staple hole 210 to upwardly force out and deform a staple23 resting thereupon against a staple forming surface 214 (FIG. 10) ofthe anvil 22. A central firing recess 216 (FIG. 3) defined within thestaple cartridge 20 proximate to the staple channel 18 allows thepassage of the bottom, horizontal portion 218 (FIG. 5) of the wedge sled126 as well as the middle pins 112 of the E-beam 102. Specifically, astaple cartridge tray 220 (FIGS. 3, 8) attaches to and underlies apolymer staple cartridge body 222 that has the staple driver recesses208, staple holes 210, and central firing recess 216 formed therein. Asstaples 23 are thus formed to either side, the sharp cutting edge 116enters a vertical through slot 230 passing through the longitudinal axisof the staple cartridge 20, excepting only a most distal end thereof.

Firing the staple applying assembly 12 begins as depicted in FIG. 10with the two-piece knife and firing bar 90 proximally drawn until thedownward projection 136 cams the middle guide 120 on the E-beam 102upward and aft, allowing a new staple cartridge 20 to be inserted intothe staple channel 18 when the anvil 22 is open as depicted in FIGS. 2,6.

In FIG. 11, the two-piece knife and firing bar 90 has been distallyadvanced a small distance, allowing the downward projection 136 to dropinto the widened hole 130 of the lower track 132 under the urging of theclip spring 144 against the upward projection 138 of the laminatetapered firing bar 94. The middle guide 120 prevents further downwardrotation by resting upon the stepped central member 124 of the wedgesled 126, thus maintaining the middle pin 112 of the E-beam within thecentral firing recess 216.

In FIG. 12, the two-piece knife and firing bar 90 has been distallyfired, advancing the wedge sled 126 to cause formation of staples 23while severing tissue 242 clamped between the anvil 22 and staplecartridge 20 with the sharp cutting edge 116. Thereafter, in FIG. 13,the two-piece knife and firing bar 90 is retracted, leaving the wedgesled 126 distally positioned.

In FIG. 14, the middle pin 112 is allowed to translate down into alockout recess 240 formed in the staple channel 18 (also see FIGS. 7,10). Thus, the operator would receive a tactile indication as the middlepin 112 encounters the distal edge of the lockout recess 240 when thewedge sled 126 (not shown in FIG. 14) is not proximally positioned(i.e., missing staple cartridge 20 or spent staple cartridge 20).

In FIG. 1, an articulation joint 32 is depicted that advantageouslybenefits from the flexible strength of the two-piece knife and firingbar 90. In FIGS. 15-18, the articulation joint 32 is depicted as a flexneck joint 300 formed by vertebral column body 302 having laterallysymmetric pairs of arcing recesses 304 that allow articulation in anarticulation plane. It is generally known to simultaneously compress andexpand respective lateral sides 306, 308 by selective movement ofcontrol rods (not shown) that longitudinally pass through the respectivelateral sides 306, 308. Depicted, however, are EAP plate actuators 310,312, each capable of powered deflection to one or both lateraldirections.

A central passage 320 (FIG. 16) defined longitudinally through thevertebral column body 302 receives a pair of support plates 322, 324that prevent buckling and binding of the laminate tapered firing bar 94.In the illustrative version, each support plate 322, 324 has a proximalfixed end 326 (FIG. 15) and a sliding end 328 to accommodate changes inradial distance during articulation. Having a firing bar 94 of a thinnerthickness is thus supported.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art.

For example, while there are a number of advantages to having a wedgesled integral to a staple cartridge, in some applications consistentwith aspects of the present invention, the wedge sled may be integralinstead to an E-beam. For instance, an entire end effector may bereplaceable rather than just the staple cartridge.

1-20. (canceled)
 21. A replaceable staple cartridge for actuation by afiring bar of a surgical instrument, wherein the surgical instrumentcomprises an empty/missing cartridge lockout for inhibiting actuation ofthe firing bar, and wherein the replaceable staple cartridge comprises:a cartridge body, comprising: a plurality of staple apertures defined inthe cartridge body; a proximal end; a distal end; and a longitudinalslot defined in said cartridge body extending from said proximal endtoward said distal end; a plurality of staples removably positioned insaid staple apertures; a plurality of staple drivers supporting saidplurality of staples, wherein each said staple driver comprises a drivesurface; a sled configured to translate longitudinally from saidproximal end toward said distal end, wherein said sled comprises aplurality of wedges configured to drivingly engage said drive surfacesof said staple drivers; and a mechanism configured to overcome theempty/missing cartridge lockout.